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Chiral metal-organic frameworks (chirMOFs) have been widely considered on enantioselective adsorption/separation, asymmetric catalysis, biological and nonlinear optical applications. However, chirMOFs are facing a great challenge in development of chiroptical thin films with circularly polarized luminescence (CPL) property. Here, we first report CPL thin films by encapsulating achiral lanthanide complexes Ln(acac)3 (Ln = EuaTbbGdc) into the pores of surface-coordinated chirMOF thin films (SURchirMOF) [Zn2(cam)2dabco]n with layer by layer (lbl) encapsulation strategy. Due to the unique combination of chiral porous MOF and adjustable luminescent complexes in the host-guest thin films, the obtained Ln(acac)3@SURchirMOF possess strong and tunable CPL property with high dissymmetry factors. The compared CPL and fluorescent lifetime results show that the advantage of this preparation strategy can effectively achieve energy transfer from Ln(acac)3 to SURchirMOF, resulting in an excellent CPL performance. This study not only provides a novel strategy to develop new types of chiral thin films but also offers an efficient approach for tunable chiroptical applications.

Two-dimensional (2D) metalloporphyrin-based MOF thin films possessing abundant π-π interactions are promising materials for photoelectronic devices, but no reports on fabrication of photodetectors are available so far. Herein, a series of 2D MOF Zn

The design and development of highly efficient electrocatalysts are very important in energy storage and conversion. As a kind of inorganic organic hybrid material, metal-organic frameworks (MOFs) have been used as electrocatalysts in electrocatalytic reactions due to their structural diversities and fascinating functionalities. Particularly, MOF thin films are coordinated on substrate surfaces by a liquid phase epitaxial (LPE) layer by layer (LBL) growth method (called surface-coordinated MOF thin films, SURMOFs), and recently have been studied in various applications due to their precisely controlled thickness, preferred growth orientation and homogeneous surface. In this review, we will summarize the preparation and electrocatalysis of SURMOFs and their derived thin films (SURMOF-D). The SURMOF based thin films possess diverse topological structures and flexible properties, providing abundant catalytically active sites and fast charge transfer for efficient electrocatalytic performance in the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CRR), supercapacitors, tandem electrocatalysis and so on. The research challenges and problems of SURMOFs for electrocatalytic applications are also discussed at the end of the review.

Bifacial dye-sensitized solar cells (DSSCs) are regarded as promising solar energy conversion devices with high efficiency and less resource consumption. In this work, a highly transparent and efficient counter electrode (CE) is fabricated by introducing highly dispersed single Pt atoms doped into the van der Waals layer-by-layer epitaxially grown Zn-TCPP thin film (Zn-TCPP-Pt). The resulting Zn-TCPP-Pt CE has similar catalytic activity to commercial Pt CE but shows a better light transmission capacity in the range of visible light. The bifacial DSSC with Zn-TCPP-Pt thin film CE achieves high power conversion efficiencies of 5.48 and 4.88% under front-side and rear-side irradiation, respectively. With maximized atomic efficiency, excellent performance was obtained with about 1% Pt content and highly transparent CEs. Therefore, the light energy resource utilization rate of such less Pt and transparence CE is greatly improved in bifacial dye-sensitized solar cells, making it a promising candidate to replace Pt CE.

Cerium (IV)-based metal-organic frameworks (MOFs) are highly desirable due to their unique potential in fields such as redox catalysis and photocatalysis. However, due to the high reduction potential of Ce(IV) species in solution, it is still a great challenge to synthesize Ce(IV)-MOFs with novel structures, which are extremely dominated by the hexanuclear Ce-O cluster inorganic building units (IBUs). Herein, a Ce-O chain IBU containing Ce(IV)-MOF CSUST-3 (CSUST: Changsha University of Science and Technology) was successfully prepared guided by the kinetic stabilization study of UiO-66(Ce)-NDC (H 2 NDC = 2,6-naphthalenedicarboxylic acid). Furthermore, owing to the superior redox activity, Lewis acidity and semiconductor-like behavior incurred by Ce 4+ , activated CSUST-3 was demonstrated to be an excellent catalyst for CO 2 chemical fixation by virtue of one-pot synthesis of styrene carbonate from styrene and CO 2 under mild conditions (1 atm CO 2 , 80 °C, and solvent-free), as well as to be a remarkable co-catalyst-free photocatalyst for overall water splitting (OWS), which exhibits 59 μmol∙g -1 ∙h -1 of H 2 and 22 μmol∙g -1 ∙h -1 of O 2 under simulated sunlight irradiation (Na 2 S-Na 2 SO 3 as sacrificial agent).

Electron delocalization in aromatic materials significantly impacts their third-order nonlinear optics (NLO). Despite organometallic complexes with Craig-Mobius aromaticity attracting great attention for their unusual physicochemical properties, their third-order NLO have been little studied to date. Herein, 12 Craig-Mobius aromatic organometallics with a stable structure similar to osmapentalyne, namely, carbolong complexes, are screened by DFT. They exhibit high third-order NLO responses because of the d and p electron delocalization in the organometallic ring. Furthermore, electron-hole distribution analyses draw a conclusion that extending the conjugated plane will increase the π-conjugation system to enhance the local excitation in the plane, and the introduction of typical aromatic ligands can result in the organometallic ring-to-ligand charge transfer (RLCT), which are effective methods to improve the third-order NLO response. This study opens a new window in the application of Craig-Mobius aromatic complexes and provides a new approach for third-order NLO materials design.

The development of metal-organic frameworks (MOFs) with nonlinear optical (NLO) properties is of pronounced significance for optical devices. Herein, a series of 2D MOFs ZnTPyP(M) (TPyP = 5,10,15,20-tetrakis(4-pyridyl)porphyrin, M = Cu, Ni, Mn, H2) films with [010]-orientation growth composed of ultrathin nanosheets from a pyridylporphyrinic ligand are first obtained by using a liquid-phase epitaxial (LPE) layer-by-layer (lbl) growth approach. ZnTPyP(M) films show a giant nonlinear optical limiting (OL) response and can be modulated by tuning the type of metalloporphyrinic ligands. As a result, ZnTPyP(Cu) film exhibits the highest nonlinear absorption coefficient of 5.7 × 10-6 m/W compared to other reported NLO materials. Density functional theory calculations were consistent with the experimental results, revealing that the tunable π-π* local excitation and the increased delocalization of the metalloporphyrinic group regulate the NLO performance of ZnTPyP(M) films. These findings provide new insight into the effect of 2D porphyrinic MOFs toward the NLO response and offer new film candidates for nonlinear OL application.

Developing efficient and inexpensive oxygen evolution reaction (OER) catalysts is one of the critical issues in energy storage and conversion technology. Herein, an oriented thin film of 3-D MOF Co/Ni(BDC)2TED (BDC = 1,4-benzenedicarboxylate; TED = triethylenediamine) nanosheet arrays is first obtained on Cu foam by a liquid-phase epitaxial layer-by-layer growth approach. The obtained thin film of bimetallic MOF nanosheet arrays has preferred growth with [001]-orientation and strong adhesion on the substrates without the use of binder materials, which provides more accessible active sites for electrocatalytic performance. The OER activity of such surface-mounted MOF nanosheet arrays can be optimized effectively via tuning the thicknesses and Co/Ni ratios. The Co/Ni(BDC)2TED grown on Cu foam with 40 cycles at a Co/Ni ratio of 1/1 shows superior OER activity with required overpotentials of 260 and 287 mV to achieve current densities of 10 and 50 mA cm−2 and excellent stability. The experiments and theoretical calculations reveal that the synergistic effect of Co/Ni and rich metal sites dominated by nanosheet interfaces improve the electrocatalytic activity. This work provides more insight into the OER activity of the MOF thin film as an electrode material and presents a new strategy for developing promising highly efficient electrocatalysts in practical applications.

The potential of metal–organic frameworks (MOFs) for applications in optoelectronics results from a unique combination of interesting photophysical properties and straightforward tunability of organic and inorganic units. Here, it is demonstrated that using MOF approach chromophores can be assembled into well‐ordered 1D arrays using metal‐oxo strands as lead structure, and the resulting porphyrinic rows exhibit unique photophysical properties and allow the realization of highly sensitive photodetectors. A porphyrinic MOF thin film, In‐TCPP surface‐coordinated MOF thin films with [021] orientation is fabricated using a layer‐by‐layer method, from In(NO3)3 and TCPP (5,10,15,20‐(4‐carboxyphenyl)porphyrin). Detailed experimental and theoretical analysis reveals that the assembly yields a structure where In‐oxo strands running parallel to the substrate fix the chromophoric linkers to yield 1D arrays of porphyrins. The frontier orbitals of this highly anisotropic arrangement are localized in these columnar arrangements of porphyrins and result in high photoactivity, which is exploited to fabricate a photodetector with record (as compared to other organic materials) responsivity in visible regime of 7.28 × 1014 Jones and short rise/fall times (0.07/0.04 s). This oriented MOF thin film‐based high‐sensitive photodetector provides a new avenue to use inorganic, stable lead structures to assemble organic semiconductors into regular arrays, thus creating a huge potential for the fabrication of optoelectronic devices., Highly photoactive, porphyrinic metal–organic framework (MOF) thin films are grown on substrates using layer‐by‐layer process. The unusual architecture of this particular MOF consists of In‐oxo chains acting as lead structure to obtain highly ordered 1D arrays of porphyrins. The MOF thin film is successfully integrated in a visible light photodetector with record sensitivity, 7.28 × 1014 Jones.

N-heterocyclic carbenes (NHCs) have attracted increasing attention on surface assembly due to their strong metal binding property, but an NHC-modified metal surface as a new growth platform to assemble other functional materials is still a challenge. Here, we report the preparation and chiral sensing properties of homochiral metal-organic framework thin films on carboxyl-containing NHC self-assembled monolayer-modified gold (Au(NHC)) substrates. By using a liquid-phase epitaxial layer-by-layer method, enantiopure [Cu2(cam)2dabco]n thin films with preferred [110] crystal orientation have been successfully grown on Au(NHC) surfaces. The results of electrochemical cyclic voltammetry and quartz crystal microbalance uptakes of (R)- and (S)-1-phenylethanol show that the chiral porous thin film on the robust Au(NHC) surface has good enantiomeric electrochemical recognition and enantioselective adsorption. The present work is a new step to develop metal-NHCs as surface platforms for the preparation of multifunctional thin films for sensing applications.

The realization of encapsulating a functional guest into porous metal–organic frameworks-based thin films for optimizing and improving electrocatalysis remains a significant challenge. In this work, an Fe bis(salicylaldehyde)ethylenediimine (Salen) compound Fe(Salen) encapsulated cobalt-porphyrin framework PIZA-1 (Fe(Salen)@PIZA-1) thin film with different surface compositions was successfully developed by using a modified epitaxial layer-by-layer approach. After calcination, this composite Fe(Salen)@PIZA-1 derived thin film is first developed as oxygen evolution catalyst which attained precise control on the surface composition. The electrochemical results showed that this unique surface modified material has a good catalytic activity for OER (η = 340 mV at 10 mA cm–2) and long-term stability. This strategy gives an insight into developing a highly active, nonprecious encapsulated thin film in electrochemical energy devices.

Here we report an effective approach for preparing hollow carbon nanospheres with Cu–TiO2 from a Ti precursor encapsulated surface mounted MOF (SURMOF) coating. Firstly a core–shell structured Cu-based SURMOF HKUST-1 on SiO2 nanospheres (SiO2@HKUST-1) with a thin and homogeneous shell coating has been prepared by a liquid-phase epitaxial layer by layer immersion method. Then the uniform SiO2@HKUST-1 nanospheres were loaded with a Ti precursor Ti(O-ipr)4, followed by calcination at 800 °C; hollow carbon nanospheres with Cu–TiO2 (Cu–TiO2/C) could be obtained after etching SiO2 nanosphere templates. As a result of their unique structure, such hollow, thin, uniform and homogeneous Cu–TiO2/C nanospheres had efficient photocatalytic H2 production and excellent recyclability under simulated sunlight irradiation. The method developed here provides a new approach for the preparation of hollow hybrid carbon nanospheres with various applications.

Metal–organic framework (MOF) thin films are important in the application of sensors and devices. However, the application of MOF thin films in organic field effect transistors (OFETs) is still a challenge to date. Here, we first use the MOF thin film prepared by a liquid-phase epitaxial (LPE) approach (also called SURMOFs) to modify the SiO2 dielectric layer in the OFETs. After the semiconductive polymer of PTB7-Th (poly[4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]) was coated on MOF/SiO2 and two electrodes on the semiconducting film were deposited sequentially, MOF-based OFETs were fabricated successfully. By controlling the LPE cycles of SURMOF HKUST-1 (also named Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate), the performance of the HKUST-1/SiO2-based OFETs showed high charge mobility and low threshold voltage. This first report on the application of MOF thin film in OFETs will offer an effective approach for designing a new kind...

A palladium catalyst (Pd-Cs) encapsulated metalloporphyrin network PIZA-1 thin film with bifunctional properties has been developed through a modified epitaxial layer-by-layer encapsulation approach. Combining the oxidation activity of Pd-Cs and the acetalization activity of the Lewis acidic sites in the PIZA-1 thin film, this bifunctional catalyst of the Pd-Cs@PIZA-1 thin film exhibits a good catalytic activity in a one-pot tandem oxidation-acetalization reaction. Furthermore, the surface components can be controlled by ending the top layer with different precursors in the thin film preparation procedures. The catalytic performances of these thin films with different surface composites were studied under the same conditions, which showed different reaction conversions. The result revealed that the surface component can influence the catalytic performance of the thin films. This epitaxial encapsulation offers a good understanding of the tandem catalysis for thin film materials and provides useful guidance to develop new thin film materials with catalytic properties.

Metal–organic frameworks (MOFs) containing rich transition metal ions and functional ligands have attracted interest for the non-noble metal oxygen evolution reaction (OER). However, the realization of MOF-based thin films for optimizing and improving electrocatalysis remains a significant challenge. In this work, we report a homodispersed CeO2 encapsulated cobalt–porphyrin network derived thin film by epitaxial encapsulation approach for optimizing and improving OER performance. The OER activity can be optimized effectively via tuning the thicknesses and calcination temperatures of the cobalt–porphyrin network PIZA-1 thin film. After loading a Ce(III) coordination compound into PIZA-1 by the epitaxial encapsulation method and calcination at 400 °C, a thin film of PIZA-1 derivative with homo-dispersed CeO2 was obtained successfully for greatly improved electrocatalytic OER performance (an overpotential of 370 mV at 10.0 mA cm−2). The work presented here will be extended to the fabrication of other composite thin film electrode materials for high electrocatalytic performance.

Development of chiral metal-organic frameworks (MOFs) for circularly polarized luminescence (CPL) is a challenging but important task. In this work, we report a first example of azapyrene-based chiral MOF thin films [Zn2Cam2DAP]n grown on functionalized substrates (named SURchirMOF-4) for CPL property. By using a liquid-phase epitaxial layer-by-layer method, the resulted SURchirMOF-4 was constructed from chiral camphoric acid and 2,7-diazapyrene ligand, which has high orientation and homogeneity. The circular dichroism, CPL, and enantioselective adsorption results show that SURchirMOF-4 has strong chirality and CPL property as well as good enantioselective adsorption toward enantiomers of methyl-lactate. The synthesis of azapyrene-based chiral MOF thin films not only represents an ideal model for studying the enantioselective adsorption, but also will be a valuable approach for development of the chiral thin film exhibiting CPL property.

The reversible photochromic molecule azobenzene was encapsulated into pores of metal organic frameworks (MOFs) using a modified liquid-phase epitaxial layer-by-layer method successfully. The obtained thin film not only has an oriented, homogeneous film with effective guest encapsulation but also has an isomerization between trans- and cis-azobenzene in MOF pores under UV and visible light irradiation. Furthermore, the photoluminescent property was studied for azobenzene loaded HKUST-1 thin film with different temperature. This facile preparation strategy and optical property of photochromic guest encapsulation into porous MOF thin film will provide the development of new optical thin film materials possessing photoswitching and photoluminescent properties.

Two mononuclear Dy(III) compounds formulated as [Dy(PNO)6(H2O)2]Br3 (1) and [Dy(PNO)6(NO3)](ClO4)2 (2) have been synthesized and characterized. Single crystal X-ray diffraction studies show that chiral and kryptoracemic strcuctures are formed when different anions are introduced into the system. 1 crystallizes in the non-polar orthorhombic space group P212121, whereas 2 assembles as a kryptoracemate in the polar monoclinic space group P21. The optical activity of single crystals of these two compounds was confirmed by circular dichroism (CD) studies. Thermal gravimetric analyses (TGA) revealed that they are stable up to 376 K (1) and 428 K (2). Differential scanning calorimetry (DSC) measurements demonstrate the absence of structural phase transitions over the investigated temperature range. Magnetic studies show that both compounds are field-induced single molecule magnets (SMMs) with energy barriers of 36 (± 0.8) K for 1 and 32 (± 1.4) K for 2. Furthermore, the dielectric and ferroelectric properties of compound 2 were also investigated.

The optical and structural quality of thin films of metal-organic frameworks (MOFs) is of utmost importance for most potential applications as sensors and other optical devices. In this work, a dipping robot equipped with an ultrasonic bath has been developed to prepare thin, homogenous surface-mounted MOFs (SURMOFs) with well-defined thicknesses and orientations. SURMOFs of type HKUST-1, prepared with and without ultrasonication, were characterized by means of XRD, SEM, AFM and UV–vis spectroscopy. It was found that the MOF films prepared with ultrasonication are significantly cleaner, more homogenous and have a considerably smaller surface roughness than MOF films prepared without ultrasonication. The higher film quality results in a tremendously improved transparency, making them perfectly suited for optical applications.

This study reports an oriented and homogenous cobalt-metalloporphyrin network (PIZA-1) thin film prepared by liquid phase epitaxial (LPE) method. The thickness of the obtained thin films can be well controlled, and their photocurrent properties can also be tuned by LPE cycles or the introduction of conductive guest molecules (tetracyanoquinodimethane and C60) into the PIZA-1 pores. The study of quartz crystal microbalance adsorption confirms that the PIZA-1 thin film with [110]-orientation presents much higher selectivity of benzene over toluene and p-xylene than that of the PIZA-1 powder with mixed orientations. These results reveal that the selective adsorption of volatile organic compounds highly depends on the growth orientations of porphyrin-based metal-organic framework thin films. Furthermore, the work will provide a new perspective for developing important semiconductive sensing materials with improved selectivity of guest compounds.

Organic–inorganic hybrid lead organohalide perovskites are inexpensive materials for high-efficiency photovoltaic solar cells, optical properties, and superior electrical conductivity. However, the fabrication of their quantum dots (QDs) with uniform ultrasmall particles is still a challenge. Here we use oriented microporous metal–organic framework (MOF) thin film prepared by liquid phase epitaxy approach as a template for CH3NH3PbI2X (X = Cl, Br, and I) perovskite QDs fabrication. By introducing the PbI2 and CH3NH3X (MAX) precursors into MOF HKUST-1 (Cu3(BTC)2, BTC = 1,3,5-benzene tricarboxylate) thin film in a stepwise approach, the resulting perovskite MAPbI2X (X = Cl, Br, and I) QDs with uniform diameters of 1.5–2 nm match the pore size of HKUST-1. Furthermore, the photoluminescent properties and stability in the moist air of the perovskite QDs loaded HKUST-1 thin film were studied. This confined fabrication strategy demonstrates that the perovskite QDs loaded MOF thin film will be insensitive to air ...

Chirality is one of the essential features in our living life and exerts a wide variety of applications in enantio-adsorption/separation. However, the mechanism between chirality and enantio-adsorption/separation is very significant in homochiral porous materials; in particular, the understanding of the relationship between crystalline orientations and chiral behavior is a challenging but important mechanism. In this work, homochiral porous crystalline metal organic framework (MOF) materials were grown on hydroxyl- and carboxyl-functionalized substrates, resulting in homochiral porous thin films with different orientations. The enantioselectivity and adsorption rates in two different oriented homochiral porous thin films were studied by using gas-phase quartz crystal microbalance (QCM) experiment of chiral probe molecules. The different mass uptake and time constant showed that the chiral behavior can be obviously influenced by the crystalline orientations on the same homochiral porous thin films. This study will not only offer a good model to understand the mechanism of chiral behavior in homochiral porous materials but also provide guidance for developing new homochiral-oriented porous thin films with high enantioselectivity or enantioseparation.

We describe the fabrication of hybrid yet well-ordered porous nanoparticle (NP) arrays with full three-dimensional periodicity by embedding nanometer-sized metal-organic clusters (MOCs) into metal-organic frameworks (MOFs). Although conventional NP@MOF encapsulation procedures failed for these fairly large (1.66 nm diameter) NPs, we achieved maximum loading efficiency (one NP per pore) by using a modified liquid phase epitaxy (LPE) layer-by-layer approach to grow and load the MOF. The preformed NPs, homochiral Ti4(OH)4(R/S-BINOL)6 clusters (Ti-MOC, BINOL = 1,1'-bi-2-naphthol), formed a regular lattice inside the pores of an achiral HKUST-1 (or Cu3(BTC)2, BTC = 1,3,5-benzenetricarboxylate) MOF thin film. Exposure to the different enantiomers of methyl lactate revealed that the NP@MOF metacrystal is quite efficient regarding enantiomer recognition and separation. The approach presented here is also suited for other MOF types and expected to provide a substantial stimulus for the fabrication of metacrystals, crystalline solids made from nanoparticles instead of atoms.

Six new metal–organic frameworks (MOFs), namely, [Pb(H2IDC)2(H2O)]n (1), {[Pb(H2IEDC)2)]·3H2O}n (2), [Ca2(HIDC)2(H2O)]n (3), {[Ca2(IEDC)2(H2O)2]·H2O}n(4), {[Cd(HIDC)(H2O)]n (5), and {[Cd2(HIEDC)2·3H2O}n (6) (H3IDC = 4,5-imidazoledicarboxylic acid, H3IEDC = 2-ethyl-1H-imidazole-4,5-dicarboxylic acid) were hydrothermally synthesized and characterized. Single-crystal X-ray diffraction shows the ligand H3IDC is partially deprotonated with H2IDC– and HIDC2– forms in three corresponding compounds 1, 3, and 5, meanwhile ligand H3IEDC also presents different deportonated motifs of H2IEDC–, IEDC3–, and HIEDC2– in 2, 4, and 6, respectively. Moreover, these partially or fully deportonated ligands coordinate in the μ1 to μ5 manner to generate one-dimensional (1D) → three-dimensional (3D) coordination polymers, displaying 10 different coordination modes. Both 1 and 2 have 3D supramolecular networks assembled via hydrogen bonding interactions but different in structure topologies. Complex 1 is a 1D coordination chain a...

As a new family of hybrid inorganic–organic materials with large porosity, metal–organic frameworks (MOFs) have received attractive attention recently on encapsulating functional guest species. Although the encapsulation of luminescent guest into bulk MOFs can tune the luminescent property, the powder composite materials are limited to the application in optical sensors and devices. In the present work, we use a modified liquid-phase epitaxial (LPE) pump method for the fabrication of lanthanide coordination compounds (LCCs)-encapsulated MOF thin film on substrate with high encapsulation efficiency. The resultant composite film reveals an oriented and homogeneous composite film, in which a white light emission by tuning the LCCs of red, blue and green emission can be obtained. This strategy may open new perspectives for developing high-encapsulation-efficiency, oriented, and homogeneous solid-state lighting composite films in the application of optical sensors and devices.

Two dimensional layered like coordination polymer [Co(2,4'-bpdc)(H2O)]n containing one-dimensional double-stranded left-handed helical channels from achiral building block 2,4'-biphenyldicarboxylic acid (2,4'-H2bpdc) was reported. The resultant crystals were not racemic as evidenced by the observation of strong signals in vibrational circular dichroism (VCD) and circular dichroism (CD) spectra

A family of lanthanide-zinc coordination polymers with two different types of three-dimensional (3-D) frameworks based on 4,5-imidazoledicarboxylic acid and oxalic acid, namely, {[Ln2(H2O)2Zn4(H2O)4(ImDC)4(ox)]·6H2O}n (Ln = La (1), Nd (2), Sm (3), Eu (4), and H3ImDC = 4,5-imidazoledicarboxylic acid, H2ox = oxalic acid) and {[Ln4(H2O)4Zn4(H2O)4(ImDC)4(ox)]·2CH3OH·2H2O}n (Ln = Eu (4′), Gd (5), Dy (6), Ho (7), Er (8), Yb (9), and Lu (10)), were successfully constructed under certain conditions and characterized by elemental analysis, IR, thermogravimetric (TG), and single-crystal X-ray diffraction. The results reveal that compounds 1–4 (I structure) are isomorphous 3-D coordination frameworks containing two-dimensional (2-D) [Zn2(ImDC)2] layers and one-dimensional (1-D) Ln2(μ2-O)2(ox) sine wave-like chains with 1-D square channels, while 4′–10 coordination polymers (II structure) are also isomorphous and feature 3-D pillar-layered coordination frameworks constructed from 2-D Zn-carboxylate [Zn2(ImDC)2] layer...

Several low-dimensional Ni/Ni−Cd complexes containing the N2O2 donor tetradentate symmetrical Schiff base ligand bis(acetylacetone)ethylene-diamine (sy-H2L2), namely, [Ni(sy-L2)]2·HLa·ClO4 (2), (HLa)2·(ClO4)·(NO3) (3), [Ni(sy-L2)X]2](4,4′-bipy) (where La = 5,7-dimethyl-3,6-dihydro-2H-1,4-diazepine, X = ClO4 (4), X = NO3 (5), [Ni(sy-L2)Cd(SCN)2]n (6) and [Ni(sy-L2)·Cd(N3)2]n (7), have been synthesized from [Ni(sy-L2)]2·H2O (1). Complex 2 is a three-component discrete assembly generated from a (HLa)+ moiety bridged with a [Ni(sy-L2)] unit and ClO4− anion. A solution containing complex 2 and Cd(NO3)2 results in a mixture of 1 and 3. Further recrystallization of 1 and 3 with various auxiliary ligands provides coordination complexes 4−7 stabilized by weak hydrogen bonds in which 6 and 7 represent the first one-dimensional heteronuclear complexes based on the symmetric acacen-base Schiff base ligand.

Self-assembly of the symmetrical tetradentate N2O2 donor Schiff base ligand, that is, bis(salicylidene)trimethylenediamine (sy-H2L3), with different zinc salts has led to six anion-dependent complexes, namely, [Zn3(sy-L3)2(μ2-Cl)Cl(C2H5OH)]·C2H5OH (1), Zn[Zn(sy-L3)(μ2-NO2)(C2H5OH)]2·2H2O (2), Zn[Zn(sy-L3)(μ2-CH3COO)]2 (3), Zn(DMF)2[Zn(sy-L3)(H2O)(SCN)]2 (4), Zn[Zn(sy-L3)(μ2-HCOO)(DMF)]2·H2O (5) and Zn[Zn(sy-L3)(μ2-HCOO)]2 (6), respectively. Six compounds were characterized by elemental analyses, IR spectra, mass spectrometry and thermogravimetric analyses, of which five structures 1, 2, 4, 5, and 6 were further determined by single-crystal X-ray diffraction analyses, and compound 3 was previously reported in the literature. It was observed that μ2-bridges in these trinuclear complexes were formed through the phenolic oxygens of the ligand or the anions in the medium. In the presence of nitrite (for 2), acetate (for 3), thiocyanate (for 4), or formate (for 5−6), μ2-bridges formed between a pair of adjacent...

Self-assemblies of two unsymmetrical tridentate N2O/N2S donor Schiff base ligands, that is, 2-((2-(dimethylamino)ethylimino)methyl)phenol (HL1) and methyl-2-pyridylmethylidenehy-drazinecarbodithioate (HL2), with different cadmium salts have led to 11 anion-controlled complexes, namely, [Cd(Ln)2] [n = 1 for 1 and n = 2 for 2], [Cd(L1)(HL1)](ClO4) (3), [Cd(HL2)(L2)](ClO4)(H2O) (4), [Cd(L2)Cl2] (5), [Cd(L1)Cl]2 (6), [Cd(L1)(NO3)]2 (7), [Cd(L2)(NO3)(CH3OH)]2 (8), [Cd(L2)(NO3)(H2O)]2 (8a), [Cd2(L1)2(SCN)2]n (9), and [CdL2(SCN)2]n (10), respectively. Eleven compounds were characterized by elemental analyses, IR spectra, MS and thermogravimetric analyses, of which 10 structures 2, 3, 4, 5, 6, 7, 8, 8a, 9, and 10 were further determined by single-crystal X-ray diffraction analyses. The compounds 2, 3, and 4 are mononuclear, in which the neutral molecule unit CdII(L2)2 (in 2) as well as cation units [CdII(HL1−2)(L1−2)]+ (L1 for 3 and L2 for 4) are respectively connected by hydrogen bonds C−H···S, O−H···O, and C−H·...

We demonstrate the realization of hierarchically organized MOF (metal-organic framework) multilayer systems with pronounced differences in the size of the nanoscale pores. Unusually large values for the lattice constant mismatch at the MOF-MOF heterojunctions are made possible by a particular liquid-phase epitaxy process. The multiheteroepitaxy is demonstrated for the isoreticular SURMOF-2 series [ Liu et al. Sci. Rep. 2012 , 2 , 921 ] by fabricating trilayer systems with lattice constants of 1.12, 1.34, and 1.55 nm. Despite these large (20%) lattice mismatches, highly crystalline, oriented multilayers were obtained. A thorough theoretical analysis of the MOF-on-MOF heterojunction structure and energetics allows us to identify the two main reasons for this unexpected tolerance of large lattice mismatch: the healing of vacancies with acetate groups and the low elastic constant of MOF materials.

A robust porous pillar-chained 3-D Cd-framework, {[Cd2(μ3-OH)2(cpt)2]·(H2O)}n (1) (Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole), containing 1-D square nanotubular channels with impressive selective sorption for CO2 over N2/H2 and interesting guest-driven tunable luminescence is reported.

Through a two-step synthetic strategy, four d10 Schiff-base complexes CdZn(DMF)(La)(NO3)2 (1), Cd[Zn(La)Cl]2·H2O (2) and [Cd(DMF)LbS]2·2H2O (S = NO3, 3; Cl, 4) (H2La = N,N′-bis(3-methoxy-salicylidene)phenylene-1,2-diamine, HLb = 2-(1H-benzoimidazol-2-yl)-6-methoxy-phenol) have been successfully constructed by the solvothermal reaction of Cd(NO3)2/CdCl2 with Zn(La)/Zn(Lb)2, and characterized by EA, IR, FAB-MS and TG, in which 1, 2 and 4 were confirmed by single crystal X-ray diffraction. The results reveal that 1 is the first 3d-4d hetero-dinuclear compound based on H2La, however, 2 is a CdZn2-type compound reported previously. 3 and 4 are the first examples of dinuclear compounds containing ligand HLb. Moreover, luminescence and biological activities of the four compounds and two ligands H2La/HLb are investigated.